This invention generally relates to the art of optical fibers and, particularly, to a method of cross-connecting or reorganizing the individual optical fibers of a plurality of fiber optic ribbons.
Fiber optic circuitry is increasingly being used in electronics systems where circuit density is ever-increasing and is difficult to provide with known electrically wired circuitry. An optical fiber circuit is formed by a plurality of optical fibers carried by a dielectric, and the ends of the fibers are interconnected to various forms of connectors or other optical transmission devices. A fiber optic circuit may range from a simple cable which includes a plurality of optical fibers surrounded by an outer cladding or tubular dielectric to a more sophisticated optical backplane or flat fiber optic circuit formed by a plurality of optical fibers mounted on a substrate in a given pattern or circuit geometry.
One type of optical fiber circuit is produced in a ribbonized configuration wherein a row of optical fibers are disposed in a side-by-side parallel array and coated with a matrix to hold the fibers in the ribbonized configuration. In the United States, a twelve-fiber ribbon has fairly become the standard. In other foreign countries, the standard may range from as a low as four to as high as twenty-four fibers per ribbon. Multi-fibers ribbons and connectors have a wide range of applications in fiber optic communication systems. For instance, optical splitters, optical switches, routers, combiners and other systems have input fiber optic ribbons and output fiber optic ribbons.
With various applications such as those described above, the individual optical fibers of input fiber optic ribbons and output fiber optic ribbons are cross-connected or reorganized whereby the individual optical fibers of a single input ribbon may be separated and reorganized into multiple or different output ribbons. The individual optical fibers are cross-connected or reorganized in what has been called a xe2x80x9cmixing zonexe2x80x9d between the input and output ribbons. The present invention is directed to various improvements in this concept of cross-connecting or reorganizing the individual optical fibers of a plurality of input and output ribbons.
An object, therefore, of the invention is to provide a new and improved method of cross-connecting or reorganizing the individual optical fibers of a plurality of fiber optic ribbons.
In the exemplary embodiment of the invention, the method includes the steps of providing a substrate having an adhesive thereon with a mixing zone within the boundaries thereof. The mixing zone has a input side and an output side. A plurality of individual optical fibers are routed onto the substrate to form a plurality of fiber optic input ribbons leading into the input side of the mixing zone. The fibers are reorganized in the mixing zone and a plurality of fiber optic output ribbons are formed leading away from the output side of the mixing zone. At least some of the output ribbons have fibers from more than one of the input ribbons. The input and output ribbons then are coated on the substrate outside the mixing zone to hold the routed ribbons in ribbon form, leaving at least portions of the fibers in the mixing zone uncoated. The coated ribbons then are stripped from the substrate, with the uncoated fibers from the mixing zone being loose. A holding device is placed about at least the uncoated loose fibers between the input and output ribbons.
According to one aspect of the invention, the individual optical fibers are routed onto the substrate by a mechanical routing apparatus having a routing head. It is contemplated that more individual optical fibers may be routed to the input side of the mixing zone than are routed away from the output side of the mixing zone. At least some of the individual fibers of at least some of the input ribbons are cut off prior to being reorganized.
According to another aspect of the invention, the input and output ribbons are gathered at opposite ends of the uncoated loose fibers. The holding device is placed over the gathered ribbons adjacent the opposite ends of the uncoated loose fibers. Other features may include the step of attaching identification labels to at least some of the input and/or output ribbons. At least some of the input and/or output ribbons may be terminated in fiber optic connectors to form an optical fiber harness.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.